class MyMath:
    # 加
    @staticmethod
    def add(a, b):
        return a + b

    # 减
    @staticmethod
    def sub(a, b):
        return a - b

    # 乘
    @staticmethod
    def mul(a, b):
        return a * b

    # 除
    @staticmethod
    def div(a, b):
        return a / b

    # 取余
    @staticmethod
    def remainder(a, b):
        return a % b

    # 开方
    @staticmethod
    def squ(a, b):
        return a ** (1 / b)

    # 取整
    @staticmethod
    def aliquot(a, b):
        return a // b


class People:
    hand = 2
    __leg = 2
    __knowledge = "一日不学，如隔三秋"
    def __init__(self, name, age, sex):
        self.__skin_color = None
        self.name = name
        self.age = age
        self.sex = sex
    @classmethod
    def zoulu(cls):
        print("跑步")
    @classmethod
    def learning(cls):
        return cls.__knowledge

    def __str__(self):
        return f"我是格式化输出"

class ChinesePeople(People):
    def zoulu(self):
        print("11路")


class AmericanPeaple(People):
    def zoulu(self):
        print("by car")


a = MyMath.add(1, 2)
print(a)

maliya = AmericanPeaple("maliya", 29, "女")
maliya._People__skincolor ="黄色"
print(maliya._People__skincolor)
maliya.zoulu()

laowu= ChinesePeople("laowu", 18, "男")
print(laowu.name)
